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A question of notation

  1. Jul 14, 2010 #1
    In a book I am reading I see the following:

    [tex]m(B_n) \uparrow m(A)\quad \textrm{if}\, B_1 \subset B_2 \subset \dots\, \textrm{and}\, \bigcup_{n=1}^{\infty} B_n = A[/tex]

    What does the up arrow signify? m(A) denotes the lebesgue measure of A if that helps.
  2. jcsd
  3. Jul 15, 2010 #2


    Staff: Mentor

    My guess is that it means "approaches from below." IOW m(Bn) < m(A) for all n, but as n increases the difference between m(Bn) and m(A) becomes smaller.
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